package AtCoderBeginnerContest353;

import java.util.Scanner;

public class A {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] a = new int[n + 10];
		int ret = -1;
		
		for(int i = 1; i <= n; i ++ ) {
			a[i] = sc.nextInt();
			if(i != 1 && ret == -1 && a[i] > a[1]) {
				ret = i;
			}
		}
		System.out.println(ret);
	}
}
